CORRELATION BETWEEN ANISOTROPY AND OXYGEN OR SUBSTITUTED CATION IN HIGH-TEMPERATURE SUPERCONDUCTORS

We analyze the effect of oxygen content and cation substitution on the anisotropy of high-T-c superconductors. On the basis of the Josephson coupled block model, the relationship between the anisotropy paramete r gamma and the oxygen doped (delta, equivalent to doped oxygen) or io n substituted (x, substituted ion) in Y-based systems is found to be g amma=gamma(0)/(1-x/x(c)) which gives a good explanation of the anisotr opy variations of the superconducting samples YBa2Cu3O7-delta, Y1-xPrx Ba2Cu3O7-delta, YBa2Cu3-xFexO7-delta, and YBa2Cu3-xZnxO7-delta; here x (c) is a fitting parameter. With the same phenomenological method, the x (or delta) dependence of gamma of La2-xSrxCuO4-y can be described a s gamma=gamma(0)/x. It can be seen that the coupling between supercond ucting layers is closely related to the doping states. (C) 1996 Americ an Institute of Physics.